american poll sicks is in terms of confronting what will be, in my opinion and the opinion of a lot of people, scientists that study the matter, the single biggest issue. here is mitt romney in october, 2011 flirting with climate denialism. >> my view is we don't know what's causing climate change on this planet. and the idea of spending trillions and trillions of dollars to reduce co2 emissions is not the right course for us. >> i want to hear someone play that tape for him. i want to hear the candidates have it out over what are you going to do? do you, mitt romney, accept the science that the planet is warming. if it is, what are you going to do about it? >> why can't the debate be pointed in that way? >> that gets to the format. my colleague, rachel, said she thought the debate format died. the debate format is going to be different in the vice presidential debate and the next presidential debate which is a town hall. hey, let them go out it. >> a different moderator might have left us with different feelings if somebody reigned it in and said you are not answering the question.